The “mohican mayfly” developped by Oliver Edwards is one of my favorites. This fly catches very well, it is almost unsinkable and holds up very well even after many hooked fish.
This fly immitates the stage in which mayflies have just pulled their wings out of the hull of the nymph and are beginning to unfold them. In the original fly, this is achieved by a parachute hackle which is pushed into a triangular shape by the foam. I have altered this a little bit and use two CDC-feathers instead.
hook: Daiichi 1160 #10
tail: mallard flank or bucktail, pheaseant tail etc.
abdomen: white foam in 2mm
wing: tan CDC and roe deer hair (I like to use the color “yellow-olive”, but anything is fine)
dubbing: e.g. “SwissCDC Argentinian Long Hare” color “natural” or any other spikey dark dubbing